1. Field of the Invention
The present invention relates to a soft focus filter and a camera using an auxiliary optical system such as the soft focus filter. More particularly, the present invention relates to a camera which allows switching between focal lengths and has an auxiliary optical system interlocked with switching of the focal length.
2. Related Background Art
Various types of compact cameras are commercially available and are popular. These compact cameras can be easily carried by users and have many functions such as automatic exposure control, automatic focus control, and flashing. In order to develop a multi-function camera which satisfies a variety of applications, multi-functional compact cameras such as bi-focal cameras are developed and commercially available on the market. In these compact cameras, an aperture/lens shutter is employed in a photographing lens so as to make the camera body compact and lightweight. In addition, some of such cameras have auxiliary optical systems such as a soft focus filter and a soft focus lens.
The soft focus filter and the soft focus lens aim at producing a soft image of an object to be photographed. Soft-tone photographing is an effective technique in portrait pictures or the like. An example of a soft focus filter is prepared by randomly forming small projections on the surface of a transparent substrate, thereby obtaining a soft focus effect. The soft focus lens is prepared by intentionally increasing aberration to provide a soft focus effect. An example of the soft focus lens is a variable aberration lens in which only spherical aberration can continuously vary.
The soft focus filter is effectively used in long-focus photographing in which only a person to be photographed is focused. In particular, the soft focus filter is effectively used together with a 70- to 80-mm portrait lens. However, short-focus photographing such as wide-angle photographing is rarely used to focus only a person to be photographed since the background cannot be out of focus and the person cannot be emphasized. Therefore, the soft focus filter is not always effective in wide-angle photographing. If the soft focus filter is used to frequently, an observer may feel poor performance of the lens and bad effects such as defocusing. Moreover, the observer may feel the soft-tone pictures are too artificial to appreciate.